Add Script tag with AMF3 content.

This doesn't parse the tag, but it at least recognizes it in the stream
and continues on. Wikipedia calls this the RTMP Stream Flex Send tag
while the RTMP docs call it a data tag containing AMF3.
Cleanup ScriptAMF3Tag

Add some simple tests and address concerns from review:
- AMF3 v. Amf3
- Unnecessary constructor override
- tag_to_class ordering
Merge pull request #1 from byronclark/additional-flv-tags

Add Script tag with AMF3 content.
Define __ne__ in OrderedAttrDict, just defining __eq__ is not enough.
Add Travis configuration.
Release v0.1.13
Back to development release 0.1.13.1
Merge pull request #2 from zaheerm/master

Add a simple script to cut flv files
Assorted cleanups and style fixes for cut-flv.

Cleanup unused imports, remove some redundant code, bring help text closer to
reality, get rid of debugging output, some small PEP8 fixes.